you are definitely too cynical: Shell is one of the largest alternative energy providers and has plenty of proprietory technology in this area.
Mobil Oil is the largest owner of solar panel technologies. If you want to build a solar panel, you will have to buy components from companies owned by Mobil or from companies who pay Mobil licensing fees to sell it...since Mobil bought up all the patents and such many years ago. They now sit on this and other technologies until such time as it economically benefits them to do otherwise.
This is more the type of thing I was alluding to.
The market for oil being what it is, it makes good business sense for companies to do this but given the current state of energy supplies and consuption it still seems a bit crass for them to do so.